A random sample of 121 checking accounts at a bank showed an ...

[scienceeasy]

A random sample of 121 checking accounts at a bank showed an average daily balance of 280 . The population standard deviation is known to be 60.
 a. Is it necessary to know anything about the shape of the distribution of the account balances in order to make an interval estimate of the mean of all the account balances? Explain.
 b. Find the standard error of the mean.
  c. Give a point estimate of the population mean.
  d. Construct a 95 confidence interval estimate for the population mean.
  e. Interpret the confidence interval estimate that you constructed in part (d).

Question 2

The process of decision making is more limited than that of problem solving.
  Indicate whether the statement is true or false

[xMRAZ]

Answer to Question 1

a. No, since the sample means will be normally distributed by the central limit theorem.
b. 5.4545
c. 280
d. 269.31 to 290.69
e. With a 95 level of confidence, we can state that the average daily balance of all checking accounts at this bank is between 269.31 and 290.69.

Answer to Question 2

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